JP4-19214A (Reference 1) discloses a suspension device for a vehicle that adjusts a vehicle height, depending on a state in front of the vehicle. The suspension device for a vehicle in Reference 1 includes an actuator that is capable of extending a suspension mounted between wheels and a vehicle body. In a case where an obstacle is detected in front of the vehicle, the actuator is controlled to extend the suspension before the vehicle passes over the obstacle such that the vehicle body is biased upward. The upward bias of the vehicle body causes the vehicle body to be lifted when the vehicle passes over the obstacle. In this manner, the vehicle avoids the obstacle.
In Reference 1, in a case where an obstacle is detected, the extension of the suspension and the upward bias of the vehicle body causes the vehicle to avoid the obstacle. In other words, since the actuator is controlled with only information related to an approach of the obstacle, there is a concern that the control may not be appropriate regarding a driving situation or the like of the vehicle.
Thus, a need exists for a vehicle-height adjusting device which is not susceptible to the drawback mentioned above.